ARS | Publication request: CHARACTERIZATION OF PATHOGENIC RHIZOCTONIA SOLANI AND R. ORYZAE OF THE PACIFIC NORTHWEST USING REAL-TIME PCR

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 20, 2006
Publication Date: June 20, 2006
Citation: Okubara, P.A., Paulitz, T.C. Characterization of pathogenic rhizoctonia solani and r. oryzae of the pacific northwest using real-time pcr. American Phytopathological Society Annual Meeting. June 15, Abstract #31, p.9.

Technical Abstract: Rhizoctonia solani and R. oryzae are the principal causal agents of Rhizoctonia root rot, damping-off and bare patch in dryland cereal production systems of the Pacific Northwest. We developed SYBR Green I-based real-time quantitative PCR (Q-PCR) assays that specifically amplified the internal transcribed spacers (ITS1 and ITS2) and 5.8S ribosomal DNA of R. solani AG-2-1, AG-8 and AG-10, R. oryzae groups I, II/III and III, and a binucleate Ceratobasidium spp. closely related to AG-I. In silico duplex stability analysis indicated that our Q-PCR primers would recognize isolates from Australia, Japan and other countries. Quantification limits ranged from 10 to 30 fg (approximately 15 to 20 genome equivalents) for mycelial DNA from cultured fungi, 1 to 5 pg of pathogen DNA in soil extracts, and 0.2 to 10 pg in root extracts. In a survey of Rhizoctonia isolates collected from sites that sustained root rot and bare patch, R. solani AG-2-1, binucleate AG-I-like and R. oryzae group II/III were most prevalent. Progress in sampling soil for R. solani and R. oryzae in conventional, minimum and no-till systems will be presented.